1. Field of the Invention
The present invention relates to an automatic sewing apparatus for hemming and closing a sleeve. The apparatus is used in automatically making a tubular sleeve from a sleeve blank by sewing machines.
The apparatus for making a sleeve, such as making a short sleeve of a T-shirt, requires a device for hemming along the folded line by folding an edge of the sleeve blank in an S-form, a sewing machine for hemming the blank along the folded line, a device for folding in two the hemmed piece along a line orthogonal to the hemming line, that is, folding in halves, and another sewing machine for closing in a tubular form by sewing the edges of the folded piece together.
2. Description of the Prior Art
In the sleeve making apparatus comprising the noted devices, generally hitherto, each device was mutually separated and the sleeve making process with the apparatus is separated into steps according to the devices. That is, one operator hems with a sewing machine, and the hemmed piece once it is taken out of the sewing machine, is manually folded in halves by another operator, and the folded piece is fed into another sewing machine by another operator, then the edges of the folded blank are sewn together.
In the sleeve making process with the steps separated in such a manner, an assembly line requiring many operations is generally formed in order to improve productivity. Even in the assembly line, a waiting time between consecutive steps is likely to occur, and overall job efficiency is, consequently, not so high. Therefore, the product cost is increased and working space for folding the blank is needed aside from the space for installing two sewing machines. Overall, a large working space is required.
Contrary to the manual procedure not above U.S. Pat. No. 4,428,315 discloses a fully automated assembly for a sleeve making apparatus. In the disclosed assembly, by raising the pickup head engaged with the center line of the back side of the sleeve blank, the sleeve blank is folded in two in the vertical plane, and the free edges of the two-fold blank are put on a conveyor to convey the blank along a folding line direction, then the blank is drawn out of a pickup head and folded in halves.
The assembly disclosed in the U.S. Pat. No. 4,428,315 is a fully automatic sleeve making apparatus, and it saves labor and installation space, improves efficiency, and lowers product cost. In such an automatic sewing apparatus, however, the blank fold apparatus is very complicated, and it is necessary to pick up the entire blank to fold in two, and draw out the folded blank while sliding on the pickup head, and therefore if the blank is, for example, slippery, it is hard to fold neatly in halves, and if folded neatly, it is often deviated when drawing out from the pickup head, and finally a neatly folded blank is not obtained and it is very difficult to make the tubular sleeve as intended.